New Zealand American Submarine Ring of Fire 2007 Where There’s Smoke… FOCUS MAXIMUM NUMBER OF STUDENTS Hydrothermal vent chemistry at subduction volca- 30 noes KEY WORDS GRADE LEVEL Melting point 9-12 (Chemistry) Boiling point Solubility FOCUS QUESTION Temperature How can unusual chemical phenomena near Pressure hydrothermal vents be explained in terms of melt- Ring of Fire ing points, boiling points, solubility, temperature, Asthenosphere and pressure? Lithosphere Magma LEARNING OBJECTIVES Fault Students will be able to use fundamental rela- Transform boundary tionships between melting points, boiling points, Convergent boundary solubility, temperature, and pressure to develop Divergent boundary plausible explanations for observed chemical phe- Subduction nomena in the vicinity of subduction volcanoes. Tectonic plate MATERIALS BACKGROUND INFORMATION Copies of “Brimstone Pit Challenge Worksheet,” The Submarine Ring of Fire is an arc of active vol- one copy for each student or student group canoes that partially encircles the Pacific Ocean Basin, including the Kermadec and Mariana AUDIO/VISUAL MATERIALS Islands in the western Pacific, the Aleutian Islands (Optional) Computer projection facilities to show between the Pacific and Bering Sea, the Cascade photographs and video Mountains in western North America, and numer- ous volcanoes on the western coasts of Central TEACHING TIME America and South America. These volcanoes Two or three 45-minute class periods, plus time result from the motion of large pieces of the for student research Earth’s crust known as tectonic plates. SEATING ARRANGEMENT Tectonic plates are of portions of the Earth’s Classroom style if students are working individu- outer crust (the lithosphere) about 5 km thick, as ally, or groups of two to four students well as the upper 60 - 75 km of the underlying 1 New Zealand American Submarine Ring of Fire 2007 – Grades 9-12 (Chemistry) Focus: Hydrothermal vent chemistry at subduction volcanoes oceanexplorer.noaa.gov mantle. The plates move on a hot flowing mantle The third type of plate boundary occurs where layer called the asthenosphere, which is several tectonic plates slide horizontally past each other, hundred kilometers thick. Heat within the asthe- and is known as a transform plate boundary. As nosphere creates convection currents (similar to the plates rub against each other, huge stresses the currents that can be seen if food coloring is are set up that can cause portions of the rock added to a heated container of water). These to break, resulting in earthquakes. Places where convection currents cause the tectonic plates to these breaks occur are called faults. A well-known move several centimeters per year relative to example of a transform plate boundary is the San each other. Andreas Fault in California. See animations of different types of plate boundaries at: http://www. The junction of two tectonic plates is called a seed.slb.com/en/scictr/watch/living_planet/plate_boundaries/ “plate boundary.” Three major types of plate plate_move.htm. boundaries are produced by tectonic plate move- ments. If two tectonic plates collide more or less The volcanoes of the Submarine Ring of Fire result head-on they form a convergent plate boundary. from the motion of several major tectonic plates. Usually, one of the converging plates will move The Pacific Ocean Basin lies on top of the Pacific beneath the other, which is known as subduction. Plate. To the east, along the East Pacific Rise, new Deep trenches are often formed where tectonic crust is formed at the oceanic spreading center plates are being subducted, and earthquakes are between the Pacific Plate and the western side common. As the sinking plate moves deeper into of the Nazca Plate. Farther to the east, the east- the mantle, fluids are released from the rock caus- ern side of the Nazca Plate is being subducted ing the overlying mantle to partially melt. The new beneath the South American Plate, giving rise to magma (molten rock) rises and may erupt violent- active volcanoes in the Andes. Similarly, conver- ly to form volcanoes, often forming arcs of islands gence of the Cocos and Caribbean Plates pro- along the convergent boundary. These island arcs duces active volcanoes on the western coast of are always landward of the neighboring trenches. Central America, and convergence of the North For a 3-dimensional view of a subduction zone, American and Juan de Fuca Plates causes the vol- visit: http://oceanexplorer.noaa.gov/explorations/03fire/logs/sub- canoes of the Cascades in the Pacific Northwest. duction.html. On the western side of the Pacific Ocean, the The junction of two tectonic plates that are mov- Pacific Plate converges against the Philippine ing apart is called a divergent plate boundary. Plate and Australian Plate. Subduction of the Magma rises from deep within the Earth and Pacific Plate creates the Marianas Trench (which erupts to form new crust on the lithosphere. includes the Challenger Deep, the deepest known Most divergent plate boundaries are underwater area of the Earth’s ocean) and the Kermadec (Iceland is an exception), and form submarine Trench. As the sinking plate moves deeper into mountain ranges called oceanic spreading the mantle, new magma is formed as described ridges. While the process is volcanic, volcanoes above, and erupts along the convergent bound- and earthquakes along oceanic spreading ridges ary to form volcanoes. The Mariana and are not as violent as they are at convergent plate Kermadec Islands are the result of this volcanic boundaries. View the 3-dimensional structure of activity, which frequently causes earthquakes as a mid-ocean ridge at: http://oceanexplorer.noaa.gov/ well. The movement of the Pacific Ocean tectonic explorations/03fire/logs/ridge.html. plate has been likened to a huge conveyor belt on which new crust is formed at the oceanic spreading ridges, and older crust is recycled to 2 New Zealand American Submarine Ring of Fire 2007 – Grades 9-12 (Chemistry) oceanexplorer.noaa.gov Focus: Hydrothermal vent chemistry at subduction volcanoes the lower mantle at the convergent plate bound- of sulfur, iron, and manganese. In this lesson, aries of the western Pacific. For more informa- students will develop explanations for these and tion on plate tectonics, visit the NOAA Learning other observed phenomena based on relation- Objects Web site (http://www.learningdemo.com/noaa/). ships between melting points, boiling points, solu- Click on the links to Lessons 1, 2 and 4 for inter- bility, temperature, and pressure. active multimedia presentations and Learning Activities on Plate Tectonics, Mid-Ocean Ridges, LEARNING PROCEDURE and Subduction Zones. See the satellite and sonar 1. To prepare for this lesson, review: survey animation of the Mariana Arc Volcanic • Introductory essays for the New Zealand Chain at: http://oceanexplorer.noaa.gov/explorations/04fire/ American Submarine Ring of Fire 2007 background/marianaarc/media/sat_em_islands_video.html. Expedition at http://oceanexplorer.noaa.gov/ explorations/07fire/welcome.html; Beginning in 2002, Ocean Exploration expe- • Submarine Ring of Fire 2004 daily logs for ditions have undertaken systematic mapping March 30 and April 1 (http://oceanexplorer.noaa. and study in previously-unexplored areas of the gov/explorations/04fire/logs/march30/march30.html and Submarine Ring of Fire. Visit http://oceanexplorer.noaa.gov/explorations/04fire/logs/ • http://oceanexplorer.noaa.gov/explorations/02fire/logs/ april01/april01.html); and magicmountain/; • April 24, 25, and 29 logs from the Ring of • http://www.oceanexplorer.noaa.gov/explorations/03fire/; Fire 2006 Expedition, which Includes first- • http://www.oceanexplorer.noaa.gov/explorations/04fire/; ever images of live red lava erupting from a • http://www.oceanexplorer.noaa.gov/explorations/05fire/; submarine volcano. and You may also want to print copies of the pho- • http://oceanexplorer.noaa.gov/explorations/06fire/welcome. tographs and/or download the video vista of html Brimstone Pit. for more information about the many discover- ies, as well as still and video imagery, from 2. Briefly review the concepts of plate tectonics these expeditions. The New Zealand American and continental drift and how they are related Submarine Ring of Fire 2007 Expedition is to underwater volcanic activity and hydrother- focused on detailed exploration of hydrothermal mal vent systems. You may want to use resourc- systems at Brothers Volcano in the Kermadec Arc, es from NOAA’s hydrothermal vent Web site an area where tectonic plates are converging (http://www.pmel.noaa.gov/vents/index.html) and NOAA more rapidly than any other subduction zone in Learning Objects 1, 2, and 4 (http://www.learn- the world. ingdemo.com/noaa/) to supplement this discussion. Introduce the Ring of Fire, and describe the pro- On April 1, 2004, scientists exploring the NW cesses that produce the island arcs. Rota #1 Volcano reported that the ROPOS remotely operated vehicle (ROV) had been 3. Show students photographs and videos of engulfed by balls of molten sulfur while investigat- Brimstone Pit, or direct them to the Ocean ing a portion of the volcano known as Brimstone Explorer Web site. Provide each student or Pit. The scientists also reported that plumes of student group with a copy of the “Brimstone hydrothermal fluids extended for several kilome- Pit Challenge Worksheet,” and have each stu- ters over and around the volcano’s summit. These dent or student group develop explanations for fluids were unusual, in that they contained the observed phenomena as directed. Tell students highest concentrations of particulate aluminum that they are to use specific numeric informa- ever recorded, as well as high concentrations tion (such as solubility data) or chemical reac- 3 New Zealand American Submarine Ring of Fire 2007 – Grades 9-12 (Chemistry) Focus: Hydrothermal vent chemistry at subduction volcanoes oceanexplorer.noaa.gov tions where possible. Background essays from the THE BRIDGE CONNECTION 2004 and 2006 Ring of Fire expeditions may be www.vims.edu/bridge/ – Click on “Ocean Science helpful in developing appropriate explanations.